In a power system installed in a vehicle, a battery and loads are connected by an electrical wire, and current is supplied from the battery to the loads via the electrical wire. The electrical wire has a resistance component. Thus, in the case where current flows through the electrical wire, the electrical wire generates heat.
Here, in the case where the amount of heat that is produced per unit time from the electrical wire as a result of current flow exceeds the amount of heat that is released per unit time from the electrical wire, the electrical wire temperature rises. In the case where current of a value that causes the electrical wire temperature to rise continues to flow through the electrical wire, the electrical wire temperature continues to rise, and there is a risk of smoke being generated or fire starting from the electrical wire. In order to prevent smoke being generated or fire starting from the electrical wire, it is naturally necessary to interrupt the current flowing through the electrical wire before smoke is generated or fire starts.
JP 5381248 discloses an interrupting device for interrupting current flowing through the electrical wire before smoke is generated or fire starts from the electrical wire. This interrupting device temporally computes the electrical wire temperature from the value of current flowing through the electrical wire. In the case where the computed electrical wire temperature is greater than or equal to a predetermined temperature, a switch provided on the electrical wire is turned off, and the current flowing through the electrical wire is interrupted. Thus, smoke being generated or fire starting is prevented, due to the electrical wire temperature not rising to greater than or equal to the predetermined temperature.
With the interrupting device described in JP 5381248, computation of the electrical wire temperature is suspended, in the case where a load has stopped operating, and the calculated electrical wire temperature approximately matches the ambient temperature of the electrical wire. Power consumption related to computation of the electrical wire temperature is thereby suppressed.
However, among the loads that the battery supplies, there are, for example, loads that require constant power supply. In this case, current constantly flows through the electrical wire.
In the case where the interrupting device described in JP 5381248 is used as an interrupting device for interrupting current constantly flowing through an electrical wire, computation of the electrical wire temperature is not suspended. Accordingly, with the interrupting device described in JP 5381248, there is a problem in that power consumption related to computation of the electrical wire temperature cannot be suppressed, in the case where current constantly flows through the electrical wire.
The present invention was made in view of this situation, and an object thereof is to provide an interrupting device, an interrupting method and a computer program that are able to suppress power consumption related to computation of the electrical wire temperature, even in the case where current constantly flows through the electrical wire.